Franca, LF & Mahjoob, A 2008, 'Drilling Action of Roller-Cone Bits — Modelling and Experimental Validation', in Y Potvin, J Carter, A Dyskin & R Jeffrey (eds), SHIRMS 2008: Proceedings of the First Southern Hemisphere International Rock Mechanics Symposium, Australian Centre for Geomechanics, Perth, pp. 625-632, https://doi.org/10.36487/ACG_repo/808_62 (https://papers.acg.uwa.edu.au/p/808_62_Franca/) Abstract: This paper presents a model of the drilling response of roller-cone bits with experimental validation. First, a set of relations between the weight-on-bit (W), the torque-on-bit (T), the rate of penetration (V), and the angular velocity (, are established using the same methodology as that applied for polycrystalline diamond compacts (PDC) bits presented by Detournay and Defourny (1992) and later complemented by Detournay et al. (2008). Then, a series of laboratory tests at atmospheric pressure with roller-cone bits reported by Karasawa et al. (2002) is used to validate the proposed model. Although the results have been obtained on a limited series of rocks, they are very encouraging in regard to the potential use of this formulation to investigate the drilling action of roller-cone bits. Furthermore, it is observed that the values identified for the intrinsic specific energy are close to the respective uniaxial compressive strength (USC). This result suggests therefore that the intrinsic specific energy and uniaxial compressive strength are correlated in tests conducted at atmospheric pressure.